OBJECTIVES: To develop a laboratory model of prostatic adenocarcinoma that is hormonally responsive and biologically similar to its human counterpart. To define effects of prolactin on the normal rat prostate. APPROACH: Using a colony of Praomys (mastomys) natalensis in which animal prostate adenocarcinoma has been induced, we are implanting chemical carcinogens into the prostate of males and females and manipulating hormonal and immune systems. Castration, testosterone, estrogen, prolactin and immuran are being administered in various combinations. In Fisher 344 rats, extra pituitary glands are being transplanted under the renal capsule of recipients. After 7 and 28 days the recipients and sham-operated controls are sacrificed, blood obtained for prolactin assay, and ventral and dorsolateral prostate removed for DNA and RNA assay.